This invention relates to portable microcomputers, and more particularly to a system of illuminated indicators characterized by their conservation of battery power.
When the first microcomputer devices appeared in the late 1970's, their weight and size limited them to desktop use. However, as the utility of such devices became evident, there arose a need for devices which could be carried from the office for use at home or in some other remote location. The first "portable" microcomputers weighed in the order of 25 lbs. and were jokingly termed "luggables", typically consisting of a relatively large box of electronic components with a small CRT screen visible from one end of the box. Typical dimensions were 20" W.times.18" D.times.12" H.
The next generation of microcomputers typically took the form of a clamshell, having the display on one part of the shell. A display folded down over a base containing a keyboard and the electronic components. These "laptop" computers initially weighed well over 10 lbs. and, while portable, were too heavy and cumbersome to conveniently transport. Reduced height magnetic disk drives, thinner keyboards and other improvements brought down the size of the devices to about 14" W.times.13" D.times.2.5" H and the weight of the devices to 10 lbs. or slightly less.
Further improvements led to third generation devices, sometimes termed "notebook" computers, having dimensions in the order of 11' W.times.8.5" D.times.1.5" H. Notebook computers have roughly the footprint of an 81/2.times.11 sheet of paper, but will fit in a briefcase. Typical weight is about 5.5-7 lbs.
To achieve this remarkable reduction in size and weight, all major components of the portable microcomputer have been downsized and rendered more energy efficient. Energy efficiency translates into smaller and lighter batteries, and/or longer battery life. Through large scale integration, computer circuitry has been greatly reduced in size, weight and power consumption. Magnetic disk drives have been downsized. Advances in display technolgy have resulted in larger, brighter and higher resolution displays without increase in weight.
The portable microcomputer has evolved to the point where reductions in weight and extensions of battery life are measured in small increments.
The typical microcomputer has a number of indicator lights, typically utilizing LEDs (light emitting diodes). Light-emitting diodes, however, are known to be undesirably energy-consumptive.
In the interest of further reducing battery weight and extending battery life, there exists a need for advances in indicator light technology.